Effect of environmental variability on seabird assemblages across the Brazil–Malvinas Confluence during the austral winter

Abstract

The Argentine Continental Shelf and its shelf break are among the most productive marine areas in the world, sustaining a high biodiversity and biomass of seabirds. The at-sea distribution of these species is greatly affected by biological and physical variability. Most prior studies about assemblages of seabirds in the study area are restricted to waters south of 40°S during the austral summer. This study aims to describe and analyze the seabird assemblages associated with the Brazil–Malvinas Confluence area off the coast of northern Patagonia, Argentina during the austral winter, and the effect environmental variability exerts on species richness and abundance in pelagic areas. Data were collected during an oceanographic survey performed between May and June 2022, in continental shelf and oceanic waters (37−41°S, 53−58°W). A total of 968 individuals belonging to 21 species were observed with the Black-browed albatross, the White-chinned petrel, and the Atlantic petrel being the most abundant and frequent species recorded. The highest seabird abundances and species richness were recorded along the continental shelf and shelf break (38º00’−38º30’S). Wind direction, wind intensity, cloudiness, and atmospheric pressure had significant effects on seabird abundance and richness. The study area is of particular interest for the extraction of both living and non-renewable resources; thus, the information provided by this study can contribute to better administration of fisheries, as well as to the creation of management plans for the exploitation of non-renewable resources.